Roofing contractors frequently need to remove structures which extend through roofs, often so that replacement structures may be installed at other locations. As an example, owing to the growing popularity of the use of ridge vents, roofers are frequently asked to remove conventional roof vents—which are generally located somewhere along the slope of the roof between the roof's ridge and the roof edge—and install ridge vents as a replacement. While the installation of the ridge vent is relatively straightforward, removal of the preexisting roof vent can be time-consuming and can cause structural and practical difficulties.
Conventional roof vents generally have an upper hood and/or grille which opens onto a downwardly-extending duct, with the duct defining a square passageway (generally measuring six inches or eight inches square) through the roof into the attic or other space below. When the vent and its duct is removed, the hole left behind in the roof needs to be patched. The patch is then usually covered with a roof covering (e.g., tar paper, shingles, and/or other coverings) for protective and/or decorative purposes.
When performing the patching operation, the roofer cannot simply nail a board over the hole. This would create a raised irregularity in the roof surface with an unattractive appearance, and also would generate potential spots for increased water collection and increased weather wear. While nailing down a sheet metal patch would avoid the problem of an unsightly (and problematic) “bump,” this solution generates new problems since heating and cooling causes expansion and contraction of the metal patch, making it difficult for fasteners to strongly maintain the patch in place on the roof. Additionally, sheet metal will provide little underlying support for fasteners when shingles or other roof coverings are later affixed to the patch. Furthermore, sheet metal patches have very poor insulating qualities, and their tendency to heat and cool with the surrounding weather conditions tends to cause rapid aging of any tar paper and/or shingles placed atop them. Thus, most roof covering manufacturers request (and their warranties require) that any shingles or other roof coverings be nailed or otherwise affixed to wood surfaces. Metal patches also generate condensation which may rot away the surrounding roof area. It is therefore strongly preferred in the roofing trade that the vent hole be patched with wood.
Owing to the foregoing problems, the preferred approach in the roofing trade is to cut a strip out of the underlying roof surface, extending horizontally from the vent hole from rafter to rafter, and then nail or otherwise fast a replacement strip (generally made of plywood) to fill in the space left by the vent hole and the surrounding removed portions of the roof. In effect, a section of the roof is replaced. This process is time-consuming and expensive, particularly since the roof covering horizontally bounding the vent hole from rafter to rafter (usually tar paper and shingles) must first be removed; the replacement strip must be cut to the proper size so that it tightly fits within the surrounding roof area; and after the replacement strip is nailed down, its entire area (and the adjacent area) must be reshingled or otherwise covered with the desired roof covering, both for weather protection and so that the patched area does not visibly stand out. Apart from consuming significant time, this process can be dangerous because an appropriately-fit replacement strip is best cut on-site—i.e., on the roof itself, adjacent the hole (so the roofer may view the hole for reference purposes)—and using a saw on the inclined surface of the roof can be dangerous work. The sawdust generated from cutting activities also tends to make the roof surface slippery, which may increase the chance of accident.
The foregoing preferred patching method also suffers from other imperfections apart from its expense, time of installation, and potential danger. In particular, it can cause an “spongy spot” with respect to the surrounding roof, and the replacement strip may bow inwardly or collapse if roofers doing later roof work walk over or otherwise exert pressure on the replacement strip. Additionally, since it can be very difficult to cut a replacement strip which tightly fits within the hole created by the removed roof section, the cracks bounding the replacement strip have an increased possibility for water leakage.
As a result of the foregoing problems, it would be useful to have available new patches and patching methods which at least partially alleviate the installation time, costs, dangers, and other deficiencies of the foregoing patching methods.